Refrigerating apparatus



Patented Jan. 16, 1940 UNITED STATES PATENT OFFICE eral Motors Corporation,

poration of Delaware Dayton, Ohio, a cor- Application January 16, 1937, Serial No. 120,996

3 Claims.

This invention relates to refrigerating apparatus and more particularly to the method of and apparatus for dehumidifying air entering a cold room. The invention is particularly adaptable to cold room test rooms in which engines are tested at sub-freezing temperatures.

An object of this invention is to provide means for balancing the pressure within the room with the pressure without the room and at the same time removing moisture from the air brought into the room.

A further object of this invention is to prevent the cooling coils for a room from becomingfrosted, thereby eliminating the need for frequent defrosting.

Another object of this invention is to provide means for supplying dehumidifled fresh air into a room.

Still another object is to provide for heat exchange between the air already in the room and the incoming air.

A further object of this invention is to facilitate the removal of the moisture from the condensing surfaces.

Still another object of this invention is to eliminate leakage of air through cracks in the walls and around the doors, thereby preventing the accumulation of ice adjacent the cracks and around the doors.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred form of the present invention is clearly shown.

In the drawing:

Fig. 1 is a view, partly diagrammatic, showing my apparatus installed in a test room;

Fig. 2 is a cross-sectional view, partly diagram matic, of a modified form of my invention in- 40 stalled in a room;

Fig. 3 is a detailed cross-sectional view of my improved air inlet duct showing condensate removal means; and 4 Fig. 4 is a fragmentary cross-sectional view showing a modified form of my invention.

This in ention is particularly adaptable to cold room test rooms in which it is necessary to maintain sub-freezing temperatures over prolonged periods of time.

5 The problem of ventilating any type of cold room has been difllcult, especially where a large amount of air has been required as when engines are started and being run in the room. The incoming air contains a considerable amount of 55 moisture with the result that this moisture condenses on the cooling coils thus reducing their efliciency and requiring frequent defrosting. Besides the necessity of defrosting the cooling coils, a considerable amount of moisture accumulates in the form of ice adjacent to cracks in the walls 5 of the room and also adjacent the door with the result that each time the coils are defrosted a considerable amount of water collects on the floor and on the walls adjacent the door and other openings.

In Fig. 1 of the drawing I have shown a test room, generally designated by the reference numeral ill, in which an engine ll provided with the usual air filter I2 and exhaust I3 is shown mounted on the table l4. Air-cooling coils ii are shown placed within the room for cooling the air therein. Refrigerant is supplied to the coils by means of the usual refrigerating apparatus, generally designated by the reference numeral l1, which may be either within the room or outside of the room. The motor I8, which drives the compressor I9, is started and stopped by the switch 20 which is responsive to the pressure within the suction line 2|. The compressed refrigerant flows into the condenser 22 which may 25 be water cooled or air cooled in the usual wellknown manner. Liquid refrigerant is fed to the evaporators l6 through pipe 23 and passes through the throttling valve 24 which is provided with the usual type of thermostat 25 placed ad- I jacent to the return pipe at 26. The refrigerating apparatus operates in the well-known manner. Other types of refrigerating systems might also be used as long as they are capable of producing the required amount of cooling within the room I. v

Above the door 21 I have shown my novel air duct 28 which condenses the moisture out of the air entering the room. As shown more clearly in Fig. 3, this duct comprises a horizontal outer casing 29 which extends from a point outside of the room a substantial distance into the room. Within this casing 29 are provided a plurality of transverse cold air tubes 3| which are staggered alternately vertically of the horizontal center so 45 that the incoming air is required to travel in a tortuous path as indicated by the arrows 32.

As shown in Fig. 3, copper wool 33 is loosely packed between the cold air tubes. The cold air tubes are open at the ends and, as shown in Fig. 1, extend slightly beyond the opposite side walls of the duct 28, so that cold air from the room will circulate within the transverse tubes. With this arrangement incoming air, which passes through the duct 28, must come in contact with the cold surfaces of the transverse tubes and the cold surfaces of the copper wool between these tubes, and in so doing moisture contained by the air collects on the cold surfaces in the form of frost in those cases where the air within the room is sufiiciently cold to freeze the condensing moisture.

During tests the engine will require a considerable amount of air for its operation and, therefore, the flow of air within the duct 28 will all be in the direction of the arrows. Even without the operation of the engine, additional air may be required within the room due to the natural re-- duotion in volume resulting from the cooling of the air or due to other causes. v

The entire unit generally designated by the reference numeral 28 is removable, so that when it becomes substantially filled' with frost a new unit may be substituted therefor while the frost is being thawed out and the resultant water drained from the unit. By having two similar units one unit will always be available for use.

The air inlet duct 28 may or may not be provided with a check 34 hingedly mounted at 36 as shown in Fig. 4. The purpose of this check valve is to prevent the reverse flow of air. In

other words, air may enter the room via the duct 28 but cannot leave the room via the duct 28. The check valve 34 is biased into the closed position merely by its own weight and freely moves into open position upon the pressure outside of the room exceeding the pressure within the room. In certain installations the temperature within the room may not be low enough to freeze the condensate, and for such installations condensate removal means such as 31 shown in Fig. 3 may be provided for draining the condensate.

In Fig. 2 I have shown a modified arran ement of my apparatus. While I have described the apparatus shown in Fig. 1 as being used in combination with rooms maintained at subfreezing temperatures, the apparatus is adaptable for use in other rooms which are maintained at higher temperatures.

In Fig. 2 the reference numeral 49 designates a room and the numeral 50 designates the usual type of unitary air conditioning apparatus in which air for the room is caused to flow in thermal contact with the evaporator by means of a fan 52. Means 53 are provided for circulating outside air into the room 49 and removing the moisture from the air so entering the room and at the same time causing an interchange of heat between the incoming air and the room air. As shown, a fan 54 is provided for circulating the outside air through the main duct 55, and transverse ducts 58 similar to the transverse ducts '3! shown in the first modification carry the cool room air in thermal exchange with the incoming air. As shown in the drawing, fan 59 is provided for causing forced circulation through the transverse tubes 58.

A unit of this type when used in combination with rooms maintained at sub-freezing temperatures may be replaced by a similar unit in the event that it becomes filled with frost; or if the temperatures are not low enough to freeze the condensate, the condensate may be drained off by means of the drain such as 31 shown in Fig. 3.

These devices may also be used to advantage in installations ,where it is merely desired to have an interchange of heat between the incoming air and the room air, even though it is not desired to remove moisture from the air.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In combination with a room, means for conveying a stream of fresh air in thermal exchange relationship with a stream of room air, and means whereby said streams of air are thereafter discharged into said room, said first named means comprising a duct containing copper wool in heat. exchange relationship with air in said room.

2. In combination with a test room in which engines are tested at sub-freezing temperatures, a breather duct having one end communicating with the room and the other end communicating with an air inlet for said room, said duct containing copper wool in thermal exchange relationship with air in the room.

3. In combination with a room, means for maintaining a relatively low temperature in said room, means for removing moisture from air entering said room comprising a fresh air inlet duct disposed within said room having transverse ducts passing through the inlet duct and provided with inlets and outlets communicating directly with said room through which room air circulates whereby the fresh air is caused to flow in thermal exchange relationship with the relatively cold room air before mixing therewith.

HARRY A. COLLINS. 

